‘I’iwi (Vestiaria coccinea)

The ‘I’iwi (Vestiaria coccinea) is a striking nectar-feeding honeycreeper (Family Fringillidae) that is usually found in wet and moderately wet forests, but may also occur in dry habitats, on five of the main Hawaiian islands. It tracks flowering ‘Ohi’a (Metrosideros polymorpha) trees and other native Hawaiian flowers, making daily and seasonal movements across the upper slopes of Hawaii’s remaining native forests to exploit nectar resources. ‘I’iwi uses its robust, sickle-shaped bill to probe flowers for nectar, and it sometimes joins calling flocks of ’Apapane, ’Amakihi, other Hawaiian honeycreepers, and non-native Japanese White-eye as they track food resources.

Once very abundant throughout the Hawaiian islands, the ‘I’iwi is still common on the Big Island and Maui. The Kaua’i population is declining, and on O’ahu and Molokai they are exceedingly rare (O’ahu) or likely extirpated (Molokai). Currently, the major threat to ‘I’iwi is its susceptibility to avian diseases, particularly avian malaria which is carried and transmitted by introduced mosquitoes – one mosquito bite can result in death. As a result, their range has shrunk on each island to areas generally above 1500 meters elevation where the cold-intolerant mosquitoes and the protozoan that causes malaria are less frequent; a warming climate threatens to further raise this elevational threshold.

In addition, introduced pigs, goats, and cattle destroy the forest understory and pigs create breeding sites for mosquitoes; introduced rats, mongoose, and feral cats depredate adults, young, and eggs, and alien invasive plants and insects threaten all native forest ecosystems. Because of the species population declines, particularly on Kaua’i, O’ahu, and Molokai, and the ever growing threats, especially of climate change, the ‘I’iwi is a Bird of Conservation Concern for the US Fish and Wildlife Service, and a Focal Species for conservation action. Although uncertainty in the face of climate change is a concern, ungulate and predator control, and habitat restoration offer some hope for this and other native Hawaiian birds, at least on the highest islands. A renewed dedication to these conservation actions will be required, however.